We investigated the creation of SERS-active hierarchical substrates based on self-assembled nanospheres (HSNs). We demonstrate how the “hierarchical” approach could be systematically exploited to extend the SERS hotspots into the third dimension, by enhancing the hot-spots spatial density and intensity. The proposed hierarchical substrates take advantage of the single layer hexagonal closed packed array nanospheres (CPA). An additional layer of upper nanospheres to obtain dense and intense hot spots pattern is employed. To predict the SERS performance and to identify the promising architectures, a numerical analysis is carried out, offering design criteria, an overview of the operating mechanisms and conditions that affect the SERS behavior of substrates. We fabricated HSNs by using a self-assembling approach and the preliminary results reported. The results highlight that HSNs can be used as cost-effective SERS substrates with better performance than simpler single-layer CPA configurations.
Recent advancements in loco-regional therapy are revolutionizing the point-of-care (POC) drug delivery field, enhancing the convenience, comfort, and effectiveness of these devices for patients. New anticancer drugs have improved the therapy, but there is still significant work to be done in order to selectively target tumour cells. To bridge this gap, here, we present a minimally invasive tool based on optical fibers (OFs) integrated in a microfluidic device for light-triggered loco regional delivery of drug-loaded particles. Specifically, we, here, selected the Lab on Fiber (LOF) technology as an attractive option to guide light and trigger the drug release. LOF, indeed, enables precise drug dosing and targeted transport, laying the foundation for mini-invasive platforms in light-activated loco-regional drug delivery. The platform includes drug-loaded carriers covalently attached on the OF surface through a photocleavable linker. The OF platform has been designed to spread light from the core region towards the cladding area in order to achieve enough power density to photo-cleave the linker and release the carrier. To this aim, side-emitting and core-offset OFs optrodes have been designed, fabricated and characterized achieving power density and scattering efficiency of 30% and 5mW/cm2 and 24.9% and 4.64mW/cm2. OFs were integrated into a microfluidic device and the particle release upon light activation was quantified. The side-emitting OF microfluidic system, designed for Hepatocellular cancer therapy, released 2.60μg/ml of carriers, while the core-offset OF microfluidic system, for Breast cancer treatment, released 1.06μg/ml of carriers. This approach holds potential for improving cancer treatment outcomes
Lab-on-Fiber (LoF) technology is a research field aimed at transforming a simple optical fiber into a multifunctional probe, which exploits enhanced light-matter interaction for a variety of applications, with special aptitude for biosensing. An attractive thread in this scenario is the integration of plasmonic metasurfaces onto an optical fiber tip, known as optical fiber “meta-tips”, leading to the development of a new generation of highly sensitive optrodes. Here we report on the latest achievements concerning the investigation of LoF probes assisted by plasmonic phase-gradient metasurfaces for the detection of small molecules as well as clinically relevant cancer biomarkers in the picomolar range. The high biosensing performance, joined with huge potential for miniaturization and integration, makes this platform an excellent candidate for the development of Point-of-Care (PoC) devices aimed at real-time and label-free detection of clinically relevant biomarkers offering several advantages over conventional procedures.
The demand for highly sensitive, fast and low-cost biosensors for reliable quantification of small biomolecules or cancer biomarkers is leading to the development of a new class of devices able to change the techniques currently used for diagnosis in oncology. Lab‐on‐fiber (LoF) optrodes offer several advantages over conventional techniques for point‐of‐care platforms aimed at real‐time and label‐free detection of clinically relevant biomarkers. Moreover, the easy integration of LoF platforms in medical needles, catheters and nano-endoscopes offers unique potentials for in vivo biopsies and tumor microenvironment assessment. Here, we demonstrate the capability to improve the immobilization strategies through the use of hinge carbohydrates by involving homemade antibodies that demonstrated a significantly improved recognition of the antigen with ultra‐low detection limits. In order to create an effective pipeline for the improvement of biofunctionalization protocols to be used in connection with the LoF platform, here we first, optimized the protocol using a microfluidic Surface Plasmon Resonance device. Then we transferred the optimized strategy on LoF platform, based on Optical Fiber Meta‐tip (OFMT), for the final validation. As a clinically relevant scenario, we focused on a serological biomarker, Cripto‐1, for its ability to promote tumorigenesis in breast and liver cancer. Reported results demonstrate that the proposed approach based on oriented antibody immobilization is able to significantly improve Cripto‐1 detection with a ten‐fold enhancement versus the random approach. Therefore, our work opens new avenues in the development of high‐sensitivity LoF biosensors for the detection of clinically relevant biomarkers in the sub‐ng/mL range.
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